“It may help you to picture the computation this way. We have already seen that the neuron in its ‘resting state’ carries a charge of around -65 to -70 mV. The critical level to trigger an impulse is about -50 millivolts. (Note the threshold mark on the gauge underneath the -50 mV point.) Whenever the voltage at the axon hillock reaches that level, a neural impulse will be triggered.”